import { GirDirection } from "@gi.ts/parser";
import type { FormatGenerator } from "../generators/generator.ts";
import { ArrayType, type TypeExpression } from "../gir.ts";

import type { GirCallableParamElement } from "../index.ts";
import type { IntrospectedOptions, OptionsLoad } from "../types/index.ts";
import { getType, parseDoc, parseMetadata } from "../utils/gir-parsing.ts";
import { isIntrospectable } from "../utils/girs.ts";
import { isInvalid, sanitizeMemberName } from "../utils/naming.ts";
import type { GirVisitor } from "../visitor.ts";
import type { IntrospectedConstructor } from "./constructor.ts";
import type { IntrospectedDirectAllocationConstructor } from "./direct-allocation-constructor.ts";
import type { IntrospectedFunction } from "./function.ts";
import { IntrospectedBase } from "./introspected-base.ts";
import { IntrospectedBaseClass, type IntrospectedClassFunction } from "./introspected-classes.ts";
import { IntrospectedField } from "./property.ts";
import type { IntrospectedSignal } from "./signal.ts";

export class IntrospectedFunctionParameter extends IntrospectedBase<
	| IntrospectedClassFunction
	| IntrospectedFunction
	| IntrospectedSignal
	| IntrospectedConstructor
	| IntrospectedDirectAllocationConstructor
	| null
> {
	readonly type: TypeExpression;
	readonly direction: GirDirection;
	readonly isVarArgs: boolean = false;
	readonly isOptional: boolean = false;
	readonly isNullable: boolean = false;

	constructor({
		name,
		direction,
		type,
		parent,
		doc,
		isVarArgs = false,
		isOptional = false,
		isNullable = false,
		...args
	}: IntrospectedOptions<{
		name: string;
		parent?:
			| IntrospectedClassFunction
			| IntrospectedFunction
			| IntrospectedSignal
			| IntrospectedConstructor
			| IntrospectedDirectAllocationConstructor
			| null;
		type: TypeExpression;
		direction: GirDirection;
		doc?: string | null;
		isVarArgs?: boolean;
		isOptional?: boolean;
		isNullable?: boolean;
	}>) {
		super(name, parent ?? null, { ...args });

		this.type = type;
		this.direction = direction;
		this.doc = doc;
		this.isVarArgs = isVarArgs;
		this.isOptional = isOptional;
		this.isNullable = isNullable;
	}

	get namespace() {
		if (!this.parent) throw new Error(`Failed to get namespace for ${this.name}`);

		return this.parent.namespace;
	}

	asField() {
		const { name, parent, isOptional: optional, type } = this;

		if (!(parent?.parent instanceof IntrospectedBaseClass)) {
			throw new Error("Can't convert parameter of non-class function to field");
		}

		return new IntrospectedField({ name, parent: parent.parent, optional, type });
	}

	copy(
		options: {
			parent?:
				| IntrospectedClassFunction
				| IntrospectedFunction
				| IntrospectedSignal
				| IntrospectedConstructor
				| IntrospectedDirectAllocationConstructor
				| null;
			type?: TypeExpression;
			isOptional?: boolean;
			isNullable?: boolean;
		} = {
			parent: this.parent,
		},
	): IntrospectedFunctionParameter {
		const { type, parent, direction, isVarArgs, isOptional, isNullable, name, doc } = this;

		return new IntrospectedFunctionParameter({
			parent: options.parent ?? parent,
			name,
			direction,
			isVarArgs,
			isOptional: options.isOptional ?? isOptional,
			isNullable: options.isNullable ?? isNullable,
			type: options.type ?? type,
			doc,
		})._copyBaseProperties(this);
	}

	accept(visitor: GirVisitor): IntrospectedFunctionParameter {
		const node = this.copy({
			type: visitor.visitType?.(this.type),
		});

		return visitor.visitParameter?.(node) ?? node;
	}

	asString<T>(generator: FormatGenerator<T>): T {
		return generator.generateParameter(this);
	}

	static fromXML<
		Parent extends IntrospectedSignal | IntrospectedClassFunction | IntrospectedFunction | IntrospectedConstructor,
	>(
		parameter: GirCallableParamElement & { $: { name: string } },
		parent: Parent,
		options: OptionsLoad,
	): IntrospectedFunctionParameter {
		const ns = parent.namespace;
		let name = sanitizeMemberName(parameter.$.name);

		if (isInvalid(name)) {
			name = `_${name}`;
		}

		let isVarArgs = false;
		let isOptional = false;
		let isNullable = false;

		let type: TypeExpression;
		let direction: GirDirection;

		if (
			!parameter.$.direction ||
			parameter.$.direction === GirDirection.In ||
			parameter.$.direction === GirDirection.Inout ||
			parameter.$.direction === GirDirection.InOut
		) {
			if (name === "...") {
				isVarArgs = true;
				name = "args";
			}

			// Default to "in" direction
			direction = parameter.$.direction || GirDirection.In;

			const optional = parameter.$.optional === "1";
			const nullable = parameter.$.nullable === "1";

			if (optional) {
				isOptional = true;
			}

			if (nullable) {
				isNullable = true;
			}

			type = getType(ns, parameter);
		} else if (parameter.$.direction === GirDirection.Out) {
			direction = parameter.$.direction;
			type = getType(ns, parameter);
		} else {
			throw new Error(`Unknown parameter direction: ${parameter.$.direction as string}`);
		}

		const fp = new IntrospectedFunctionParameter({
			isVarArgs,
			type: isVarArgs ? new ArrayType(type) : type,
			direction,
			parent: parent ?? undefined,
			isOptional,
			isNullable,
			name,
			isIntrospectable: isIntrospectable(parameter),
		});

		if (options.loadDocs) {
			fp.doc = parseDoc(parameter);
			fp.metadata = parseMetadata(parameter);
		}

		return fp;
	}
}